Help with Google Nest Thermostat Leraning 4th Gen Wiring

[Graeme1984]

Hello. I wired up the nest pretty easily but the system only seems to be heating. I swapped out a honeywell th8321wf1001 with somewhat similar wiring to the prototypical but with an orange wire going to the W and white to W2. Yellow to Y. Green to G. Red to R. Blue to C. For the best I did yellow to Y1, green to G,  ref to Rc, orange to W1, white to W2 and blue to C. However something is wired incorrectly because when it cool mode the system is heating and when in heat mode the system is off. Not sure what I did wrong. Does anyone have any ideas?

[Rusell]

Hi Graeme1984,

Thank you for posting in the community. I'm sorry to hear that your heating system is behaving in reverse, it's heating when it should be cooling, and off when it should be heating. I'm here to help you!

At the moment, i need to ask a few questions to give the correct troubleshooting:

• Is your system a heat pump?
• To help us get a better picture of what's happening, do you mind sharing a photo of the old wiring of your old thermostat?
• Do you see any error code in the thermostat's display?

Keep me posted.

Best regards,

Rusell. 

[mexijone21]

It is like your reversing valve might be the issue. Since you have an orange wire going to W1, it’s possible your system is set for a heating default when it should be in cooling mode. Try switching the O/B setting in the Nest’s Pro setup (O/B wire setting) to see if that corrects the issue. Some systems use O for cooling and B for heating, so it may just be a configuration tweak.

[johncrady32 · Accepted solution]

It is like your heat pump wiring might be swapped. On many systems, the orange wire (O/B) controls the reversing valve, which determines whether the system heats or cools Try checking your Nest settings under Heat Pump Orientation—it may need to be switched from O to B or vice versa. Also, confirm that W1 and W2 are correctly assigned, as some systems don’t use both. Let us know if adjusting the setting helps.